Strain-based force, torque, and displacement instruments have conventionally included strain elements, in the form of flexures, columns, diaphragms, or shear panels. These elements react to stresses caused by tension, compression, bending, torsion, or shear. One objective of such devices has been to produce the required levels of strain in the element to actuate a strain-measuring transducer, such as a bonded resistance strain gage, while maintaining a minimum of strain and deflection in the overall structure; i.e., a high level of sensitivity to load. A further objective has been to provide compact and potentially miniature structures that incorporate adequate strain elements. Devices of the shear-panel element type have been constructed with round or rectangular blind cavities located transversely in a beam structure, leaving a thin shear panel to react to stresses as the beam is stressed. FIGS. 1 through 4 are illustrative of the prior art constructions currently in use. While these instruments have been both successful and economical, they have been limited in compactness and stiffness.
Thus, there exists a need for a compact strain-based measurement device that provides high sensitivity (high surface and strain levels) at very low levels of actuating deflection.